Methods and processes for iodine disinfection

ABSTRACT

An iodine purification process comprising; a source of fluid; means for delivery of iodine to the source of fluid for use in the purification process; the process further comprising means for recovery of the iodine and/or iodine and/or other iodine species derived from the iodine, from said fluid.

This application is the national phase under 35 U.S.C. § 371 of PCTInternational Application No. PCT/AU01/00884 which has an Internationalfiling date of Jul. 20, 2001, which designated the United States ofAmerica.

BACKGROUND

The present invention relates to treatment processes using iodine andmore particularly relates to improved methods and processes forsanitization/disinfection of water reticulation networks such as but notlimited to cooling towers, swimming pools, water tanks, waste water,sewerage and water washing of consumables such as but not limited tofood products and drinking water wherein the concentration of activeiodine in iodine enriched water used in the disinfecting processes canbe maintained within a predetermined optimum range. More particularlythe invention relates to processes and methods for disinfection usingiodine enriched water wherein the water is constantly recharged withiodine and wherein iodide and iodine bi-products and other iodinespecies may be continuously removed from the processes and converted toiodine for either recharging said water or for retention and furtherre-use in the process.

PRIOR ART

Chlorine and Iodine are well known as agents for microbiological controlin water supply systems. Iodine has a number of advantages overChlorine.

Disadvantages of chlorine used as a microbiological agent include thefollowing:

-   1 Formation of by products (trihalomethanes and    chloro-furanones—THM's) that have been found to be mutagenic and    carcenogenic and are subject to increasing worldwide government    regulation.-   2 As chlorine is a gas at room temperature it is extremely toxic.-   3 Chlorine is corrosive potentially adding a significant cost to    accelerated equipment replacement.-   4 Chlorine has high sensitivity to changes in pH and temperature and    is only effective in a narrow band of pH and to achieve this desired    pH level requires constant monitoring and adjustment.-   5 Continued use can significantly affect the quality of the wash    water that is required to be disposed of at the end of a    disinfection process leading to the growing need to treat this waste    water prior to disposal.-   6 Chlorine is required to be used in many sanitation operations    involving food stuffs at high levels (up to 250 ppm) to achieve    acceptable microbial kill rates.

While there is growing pressure to reduce bacterial loads on foodstuffsthis must be balanced against the disadvantages of increased use ofchlorine which is undesirable for the above reasons. In recognition ofthe advantages of use of iodine as a purification and disinfectingagent, a number of systems have been developed which employ moleculariodine in the sanitization of water for drinking purposes and for use inprocesses which include disinfection of sewage, foodstuffs and wastewater.

Iodine is the preferred sanitizing agent in the food industry as it isacknowledged as a more effective user friendly sanitizing agent thanchlorine. In addition, depending upon the concentrations, it is safe,can be effectively used at reduced concentrations (up to ten times less)than chlorine yet with a higher microbial kill rate. Iodine (unlikechlorine) does not produce any harmful substances such as carcinogens,and if nearly all by-products are removed, can produce anenvironmentally safe waste water. Being a solid at room temperatures andsupplied, immersed in water, the potentially harmful effects of exposureto a concentrated sanitizing agent such as chlorine are removed,significantly improving environmental work conditions. Furthermore,iodine is less corrosive than chlorine reducing corrosive effects fromthe use of a biocide.

A number of United States patents disclose the use of iodine inconjunction with processes for purification of water. For example, U.S.Pat. No. 4,888,118 discloses a water purification process in which thewater is passed through a mass of nylon 4 complex with iodine. Thetreated water is subsequently passed through nylon 4 to remove iodinefrom the water.

U.S. Pat. No. 5,176,836 discloses a new and improved water purificationprocess or method by introduction of molecular iodine into the watersupply to impart a desired iodine residual wherein the water is passedthrough an iodinated anion exchange bed wherein the concentration of I₂in the flowing water gradually decreases and the ion bed is recharged bytreatment with an aqueous iodine solution produced by flowing waterthrough a bed of iodine crystals having connections in parallel with theion exchange bed and activated periodically e.g. by a timer, by measuredflow of water or by residual level to recharge the bed. That systemprovides for long term microbiological control in water suitable forpotable activities. The bed of Iodine crystals is provided withconnections for flowing water there through to produce a concentrated(substantially saturated) aqueous iodine solution which is passedthrough the iodinated resin bed to recharge the bed with bound iodine.

One of the difficulties with the known systems is to maintain an optimumamount of active iodine delivered into the target water supply for thespecified purpose. To date there has been no effective system which caneffectively and economically guarantee the delivery of exactly the rightamount of active iodine at higher levels into the water used to washproduce in the case where iodine is used for food sanitization or intowater delivered through reticulation networks, not only to prevent wasteof iodine and economic loss but also to ensure that there is anacceptable minimum of active iodine.

Iodine recovery processes are known whose objective is to recover iodineto compensate for gradual reduction of I₂ in the flowing water and toprovide a desired iodine residual. The process described in U.S. Pat.No. 5,176,836 is distinguished from previous systems by providing acontinuous long term microbiological control process in a water supplyparticularly in space vehicle applications wherein I₂ is released intothe water stream flowing through a suitable anion exchange resin.

U.S. Pat. No. 5,919,374 discloses a method and apparatus for producingbacteria free iodine species containing drinking water for farm animalsunder continuous dynamic water flow to produce a saturated iodinespecies containing aqueous solution at a pre selected temperature andblending the saturated solution with a second water flow to produce adiluted iodine species bacterium free aqueous solution.

U.S. Pat. Nos. 4,131,645; 5,356,611; 5,464,603; 5,639,452; 6,139,731;and 6,004,465 disclose prior art processes in which iodine is employed,each of which is incorporated herein by reference. The processesdescribed in those US patents do not teach the use of means toeffectively and economically control delivery of iodine in a waterstream, nor do they disclose collection and conversion of iodide toiodine species for re use in the process.

Iodinated resin beds are known as a means for recharging a water supplywith a minimum amount of active iodine. The recharging is effected bytreatment with an aqueous iodine solution produced by flowing waterthrough a bed of iodine crystals. The iodine residual is monitored andthe bed recharged where necessary by adjusting the flow rate of waterthrough the bed of iodine crystals. This is an expensive method ofmonitoring the level of active iodine and the resin rich in bound iodineis very expensive. In addition, the capacity of the resin is limited andreloading techniques in the field would be difficult to maintain in highwater flow conditions. Also, this process is best suited to low level(<4 ppm) delivery of active iodine usually in a clean filtered waterenvironment. This is due to the slow dissolving rate of iodine fromknown iodine beds and the limitation of the release rate and saturationof the anion exchange resins.

An ideal level of active iodine to be maintained in a water supplyprocess system for food sanitization purposes is in the range of 10 ppmto 25 ppm although some applications may require higher concentrations.When iodine is used in food sanitizing applications, it may react withorganic matter in which case the active iodine can be quickly exhaustedto the point where there is none left for microbiological control. Also,iodide can build up in iodine wash water solutions causing a furtherconversion of active iodine into iodide species thereby causing afurther diminution of the bacteriocidal effect of the process.

If resins are used to deliver active iodine, this will necessitatecontinual monitoring of iodine concentration and it will also requirerecharging the target water stream with active iodine. It is expensiveto replace resin so it is ideal that the resin life be prolonged for aslong as possible. Saturation of resin with 46% weight Iodine willproduce around 4 ppm active iodine release. However, the operating rangeof these resins is limited and they all exhibit a severe depletion curvebecoming ineffective at approximately 40% saturation. In other words,there is only a narrow band of approximately 6% by way of volume withinwhich the resins will operate before requiring recharging.

Known iodine resins such as those available from the corporations DowChemicals, Purolite, Rohm & Haas etc can deliver up to 4 ppm of activeiodine but the ideal level to be maintained for food operations is 10ppm to 25 ppm. The known iodine purification processes are limited intheir applications because they;

-   do not teach a practical method of continuously delivering    concentrations of active iodine up to 25 ppm within a high volume    flow rate environment;-   do not teach how to provide for the constant removal of iodide and    iodide specie bi-products from the wash water;-   do not teach how to stop the exhaustion of active iodine by    interaction with the iodide specie present in the wash water;-   do not teach a process that can use iodine as a sanitation biocide    for use in environments that have high organic and bacteria loads;-   do not teach a process to collect iodide bi-products and convert the    iodide back into iodine;    and to date have primarily been applied to water supply systems for    drinking water. The known processes do not teach an economic method    or arrangement for maintaining the iodine level at a predetermined    optimum level. Furthermore, the prior art does not teach the    application of controlled iodine purification processes to water    reticulation networks and in such applications as fruit and    vegetable washing, fresh cut food operations, food processing    plants, swimming pools, cooling towers, town water supplies, tanks    and the like. A controlled iodine delivery process would be one in    which the level of iodine can be maintained at a predetermined    optimum level and without constant manual intervention and    monitoring. The prior art does not teach such a process alone or in    combination with a recovery process in which surplus iodine and    iodide can be recovered from the process for respective re use and    conversion to iodine for reuse.

Elemental iodine is a biocidally active form of iodine that has beenused as a water disinfectant for almost a century. It is also widelyused as a sanitizing compound in the food processing industry. Chlorinesolution (especially hypochlorites) have been widely using by growers asa sanitising wash for many fruits and vegetables. However, the strongoxidizing effect of chlorine in water with a moderate to high organicload results in a number of different complex compounds (trihalomethanesor THM) which can become a significant environmental hazard. There arestrong reasons to minimise the excessive use of chlorine on foods,particularly due to THM levels. Chlorine dips can also cause soilpollution with continuous re use on farms.

Besides the environmental and health benefits of using the iodine forwashing fresh produce, it is also reported that iodine is more activeagainst a number of organisms in water, than chlorine (Koponen et al.1993). The efficiency of iodine for the control of Escherichia coli indirty water was found to be greater than that of chlorine especially atthe higher temperature and pH values (Ellis et al., 1993). Effectivenessof iodine on pathogenic organisms at low concentration (Oliver et al.,1991) has been reported to be cost effective and less hazardous for theusers (Oliver et al., 1991).

DETAILED DESCRIPTION OF THE INVENTION

The present invention seeks to provide an improved process, method andapparatus for maintaining the level of active iodine in a process forsanitizing such consumables as foods stuffs or in a water reticulationnetwork and more particularly provides a purification process whichincludes extraction of iodide and surplus iodine from the process andsubsequent conversion of iodide to iodine for reuse within the process.

It is one object of the invention to provide a process and method forsanitization of water used in food sanitization and in reticulationnetworks that reduces labor and which requires no pre mixing ofchemicals or pH adjustment to maintain optimum levels of iodine andbiocidal action.

It is a further object to provide a process, apparatus and method thatprovides a more accurate method of delivery of a strong biocide such asiodine into a target wash water stream, wherein the process ensures suchwash water remains rich in active iodine and the process remains purewithout the build up of iodide by-products which in turn deplete iodinein a wash tank.

It is a further object of the process and method to deliver a controlledamount of iodine biocide accurately and constantly and at the same timeremoving the same amount of iodine species present in a wash water. Theprocess then ensures an accurate level of biocide is maintained at alltimes. It is a further object of the present invention to maintain aconstant pre determined active biocide level in a water stream used in avariety of applications.

It is a further object to provide an environmentally friendly system forproviding an efficacious method of controlling bacteria at the same timeas removing bi-products of the biocide used.

It is a further object of the process to provide means for accuratecontrol and measurement of a biocide in solution and further means toenable recordal of that information for confirmation of accuracy of theprocess.

It is a further object of the invention to provide the option forcontrol mechanisms to accurately measure the available biocide insolution and for that information to be used to vary the level of dosageand delivery of biocide into the process.

In one broad form the present invention comprises;

-   an iodine purification process comprising;-   a source of fluid;-   means for delivery of iodine to said source of fluid for use in said    purification process;-   the process further comprising means for recovery of said iodine    and/or iodide and/or other iodine species derived from said iodine    from said fluid.

Preferably, the process further comprises means for conversion of iodinespecies derived from the iodine delivered to said solution to iodine(I₂)wherein the iodine/iodide or the other derivative iodine species arerecovered on an anion exchange resin.

The iodine/iodide or the other derivative iodine species may beconverted via conventional chemical means for recovery of iodine. Theconversion may be performed either as part of the process or off siteremote from said process. According to one embodiment, the conversionmay be effected by an electrowinning process. Alternatively, theconversion may be performed remote from said process using green sand asa catalyst. The iodine/iodide or said other derivative iodine speciesmay be separated from the anion exchange resin by washing the resin witha solution of potassium hydroxide.

According to one embodiment, the water is charged with a predeterminedconcentration of iodine; wherein the process includes; a continuouswater supply to or for one or more applications; a source of iodineintermediate the source of the main water supply and a treatment stationfed by the main water supply; wherein delivery of the iodine ismaintained at a predetermined concentration within a predetermined rangein a water stream delivered from the water supply. The predeterminedconcentration of iodine provides a predetermined level of purificationof the water stream.

Preferably, the concentration of iodine delivered to the water stream ismaintained by use of an iodine formulation having a high surface areawhich is capable of fast dissolving in a water flow stream. The iodineconcentration is maintained in the flow stream irrespective of the flowrate, temperature of the water stream and level of contamination of saidwater. Preferably, the predetermined concentration of iodine isproportionate to a level of contamination of said water stream.

In another embodiment, the process includes an anion exchange resincapable of absorbing iodide and iodine species. The resin collects theiodine species for reuse in said process and is removable from thecollection station. The water purification process may be applied infood treatment, water reticulation installations including swimmingpools, cooling towers, water supplies, water tanks and town water.

In another broad form, the present invention comprises; a conversionprocess for conversion of iodine species to iodine (I₂) wherein theiodine species for conversion by the conversion process is derived froman iodine purification process, the process comprising;

-   a source of fluid;-   means for delivery of iodine to said source of fluid for use in said    purification process;-   the iodine purification process further comprising means for    recovery of said iodine and/or iodide and/or other iodine species    derived from said iodine from said fluid prior to conversion to I₂    by said conversion process.

Preferably the iodine/iodide or other derivative iodine species arerecovered prior to the conversion process on an anion exchangeabsorption resin. The conversion may be performed either as part of thepurification process or remote from the process by an electrowinningprocess, a catalyst or other conversion process.

Alternatively, the conversion process is performed using green sand as acatalyst.

In another broad form the present invention comprises a process for thecontinuous iodine assisted purification of water during use inapplications including the washing of consumables such as foodstuffs andin water reticulation installations; wherein, said water is charged witha predetermined concentration of iodine; wherein the process includes; acontinuous water supply to or for one or more said applications;

a source of iodine intermediate said source of said main water supplyand a treatment station fed by said main water supply; wherein saidsource of iodine is maintained at a predetermined concentration ofelemental iodine within a predetermined range in a water streamdelivered from said water supply;

wherein said predetermined concentration of iodine provides apredetermined level of purification of said water stream.

According to a preferred embodiment, the concentration of iodine ismaintained by use of an electrodeposited particulate iodine formulationhaving a high surface area which is capable of fast dissolving in awater flow stream.

The iodine concentration is maintained in the flow stream irrespectiveof the flow rate of the water stream and level of contamination of saidwater; wherein said concentration of elemental iodine in said waterstream is maintained by controlled release of iodine from said source.

In another embodiment an anion exchange release resin is charged with apredetermined amount of elemental iodine wherein the anion exchangerelease resin is located between the source of iodine and the treatmentstation. The anion exchange release resin is housed in one or moresealed containers.

The process further comprises a collecting station for collecting iodideand/or iodine or iodine species from water delivered downstream of saidtreatment station. In one embodiment, the means for collecting iodideand/or iodine species comprises an in line anion exchange collectionresin. The resin collects the iodide for conversion to iodine for reusein the process wherein the iodide and/or iodine species collection resinis removable from the collection station. The iodide is stripped fromthe resin at a location remote from the process. One means forconversion of said iodide and/or iodine species comprises anelectrochemical process conducted remote from the sanitizing process.

After collection of surplus iodine and/or iodide or other iodine speciesfrom water delivered from the treatment station, the water is eitherrecirculated through the process or dumped to waste.

Water recirculated through the process may be recharged with iodine bypassing through iodine crystals prior to entry into the treatmentstation which may comprise a reservoir.

Another means for converting iodide and/or iodine species is an in linecatalyst. Alternative conversion means comprise an in line or off siteelectrochemical process or chemical reactions. Preferably, the chemicalreactions employ the use of known oxidants which may be selected frompermanganate, dichromate, hydrogen peroxide, bromate, iodate, chlorate,cerium, copper, chlorine and bromine.

In another broad form of a method aspect, the present inventioncomprises;

-   a method of iodine purification in a fluid stream charged with a    source of fluid; the method including the steps of;-   a) providing means for controlled delivery of iodine to said source    of fluid for use in said purification process and delivering iodine    to said fluid;-   b) recovering said iodine and/or iodide and/or other iodine species    derived from said iodine from said fluid after said purification.

The method comprises the further step of converting of iodine speciesderived from the iodine delivered to the solution to iodine (I₂) and thefurther step of prior to conversion, collecting the iodine/iodide orsaid other derivative iodine species on an anion exchange resin. Theconversion may be performed remote from said process. Alternatively, acollection and conversion may be in line as part of the purificationprocess. The conversion step is according to one embodiment performed byan electrowinning process.

According to another embodiment of the method aspect, the conversionstep is performed remote from the process using green sand as acatalyst.

The method preferably comprises the further step of separating theiodine/iodide or said other derivative iodine species from the anionexchange resin wherein the separation step may comprise washing theresin with a solution of potassium hydroxide.

According to the method aspect, the supply water is charged with apredetermined concentration of iodine; wherein the process includes; acontinuous water supply to or for one or more applications;

a source of iodine intermediate said source of said main water supplyand a treatment station fed by said main water supply; wherein saidsource of iodine is maintained at a predetermined concentration ofelemental iodine within a predetermined range in a water streamdelivered from said water supply;

wherein the predetermined concentration of iodine provides apredetermined level of purification of the water stream.

Preferably, the concentration of iodine delivered to the water stream ismaintained by use of an iodine formulation which has a high surface areaand is capable of fast dissolving in a water flow stream wherein theiodine concentration is maintained in the flow stream irrespective ofthe flow rate, temperature of the water stream and level ofcontamination of said water.

Preferably, the predetermined concentration of iodine is proportionateto the level of contamination of said water stream. The method maycomprise the further step of charging an anion exchange release resinwith a predetermined amount of elemental iodine. The method steps of thewater purification process may be applied in food sanitization, waterreticulation installations including swimming pools, cooling towers,water supplies, water tanks and town water.

According to one embodiment there is provided a purification process foruse in the purification of food products and of water in installationssuch as swimming pools, cooling towers, domestic water reticulationnetworks, portable water supplies, water tanks and the like.

In a typical arrangement according to one embodiment of the invention,there is provided a specially prepared iodine (BioMaxA™) located in asealed cartridge or canister enclosed in a sealed canister. ThisBioMaxA™ iodine has a high surface area relative to existing forms ofcommercially available iodine and is specially formulated to quicklydissolve in water providing a constant saturated solution of iodine. Thelevel of saturation is affected by temperature. The sealed canister isattached to a water flow line for delivery of a predeterminedconcentration of saturated iodine solution in order to achieve arequired final concentration of iodine for the selected sanitationapplication. Preferably, a control valve is used to ensure that a targetconcentration of saturated iodine solution is released into the mainwater flow. The control valve is responsive to or is preset totemperature variations and final iodine concentration required. Anamalgamation of both water streams being the main water flow and thesaturated solution charged with iodine ensures a final dilutedconcentration of iodine is achieved in line with process requirements.

The process may be computer controlled to maintain predetermined optimumoperating levels. Known methods of computer control of fluid flowparameters can be used to monitor iodine and iodide levels. These mayinclude the use of probes and/or sensors located to detect predeterminedparameter levels. Where there is no or minimal bacteria in theinstallation or food stuff under treatment, iodine may not be used up.Thus, iodine demand will be a function of microbiological load andreactions with organic matter. As iodine can be quickly exhausted whenit reacts with organic matter, (albeit to a lesser extent thanchlorine), there is a need to continually monitor available iodine formicrobiological control.

According to one embodiment, the process includes the use of aconversion process to process the iodide species captured by the anionexchange resins and convert these iodide species back to a preferredBioMaxA™ iodine. Although there are known means for this conversion theyare expensive and inefficient and have not been applied in a continuousiodine sanitization process. The present invention seeks to provide aprocess for the purification of water used in sanitizing food stuffs andin installations which employ water reticulations wherein the processincludes a step of conversion of iodide to iodine in an efficient andeconomic manner.

According to one embodiment, the process includes the collection ofiodine and iodide surplus to the process on a series of two or moreanion exchange resin columns. Once collected, these resin columns aretaken offsite for processing. This involves firstly stripping of theiodide from the resin columns. There are a number of different ways thatthis could be achieved—for example by the use of a solution of potassiumhydroxide. According to one embodiment, once stripped, this solution ismixed with sulphuric acid and results in the production of potassiumsulfide, hydrogen gas and a concentrated iodide solution. This iodidesolution is then passed on to the next stage of the conversion processfor production of iodine.

According to one embodiment, the conversion process involves the use ofan electrochemical electro-winning process (such as that described inthe applicant's co pending Australia patent application No PQ8915) whichis capable of conversion of iodide to iodine to supplement existingiodine used in the system. This electro-winning process generates aparticular form of high surface area fast dissolving iodine crystalswhich precipitates from the solution and is then available for reuse inthe process.

In one broad form the present invention comprises:

A process for sanitizing water used in the washing of consumables suchas foodstuffs and in installations using water reticulation such asswimming pools, water supplies, cooling towers, water tanks, town waterby washing or flushing with iodine enriched water: means for maintaininga concentration of elemental iodine within a predetermined range in awater stream used in said sanitizing process;

the process comprising: a closed or open water reticulation networkincluding;

a source of main water supply for delivery to a treatment station:

a source of iodine disposed intermediate said source of main watersupply and said treatment station:

wherein effluent from said treatment station flows through at least tworeceptacles for holding an anion exchange collection resin capable ofcollecting said iodine and iodide created by the process which isretrieved for further use in the process.

Preferably, the anion exchange resin receptacles holding iodidecollected from water exiting said treatment station are taken off sitefor stripping of iodide and conversion to iodine using a conversionprocess to regenerate iodine for further reuse in the process.

According to one embodiment, said at least two receptacles dischargeeffluent for reuse in the process or for discharge from the process.

According to an alternative embodiment, the process further comprises atleast one receptacle for holding an anion exchange release resin chargedwith a predetermined amount of elemental iodine and disposedintermediate said source of iodine and said treatment station

In another embodiment the process includes a conversion station forconversion of iodide and/or iodine species. According to thisembodiment, the conversion station is in line and is disposedimmediately prior to the iodine crystal canister/s but without an anioncollecting resin cartridge; wherein the water stream is recirculated.

In its broadest form the present invention comprises;

A purification process using iodine for decontamination, the processcomprising;

-   a source of water for one or more water consuming applications and    providing a water stream in said process;-   a delivery station intermediate said source of water and-   a treatment station;-   a source of iodine at the delivery station and means to enable    release into said water stream of said iodine; wherein the iodine in    said water stream is maintained at a predetermined concentration to    provide a predetermined level of purification of said water stream    and/or objects in contact with said water stream in the treatment    station;-   means for recovery from said water stream of said iodine and/or    iodide and/or other iodine species derived from said iodine; and-   means for conversion of all said recovered iodine species derived    from said iodine delivered to said stream to iodine as used in this    system.

In its broadest form of the method aspect the present inventioncomprises:

-   a method of iodine purification of a water stream and/or objects    therein; the method including the steps of;-   a) providing a source of water for one or more water consuming    applications and providing a water stream as part of a the    purification process;-   b) providing an iodine delivery station intermediate said source of    water and a treatment station;-   c) providing a source of iodine at the delivery station and means to    enable controlled release into said water stream of said iodine;-   d) charging water with a predetermined concentration of the high    surface area iodine-   e) recovering said iodine and/or iodide and/or other iodine species    derived from said iodine from said fluid after said purification;-   f) converting the iodine and/or iodide and/or other iodide species    to iodine (I2)for reuse in the purification process.

In another broad form according to the method aspect, the presentinvention comprises; a method for sanitizing water used in the washingof consumables such as foodstuffs and in installations using waterreticulation such as swimming pools, water supplies, cooling towers,water tanks, town water by flushing or washing with iodine enrichedwater wherein a concentration of elemental iodine is maintained within apredetermined range in a water stream; the method comprising the stepsof:

-   a) placing a source of iodine intermediate a source of main water    supply and a treatment station fed by said main water supply:-   b) placing at least one receptacle for containing an anion exchange    release resin charged with a predetermined amount of elemental    iodine between said source of elemental iodine and said treatment    station;-   c) providing a conversion station capable of converting iodide to    iodine at ambient temperatures using air as an oxidant and placing    the station in communication with water exiting said treatment    station;-   d) and/or passing water through said source of iodine for enriching    said main water supply with iodine, prior to introducing water from    said main water supply into said at least one release resin    receptacles; and/or-   e) passing water through said at least one receptacle containing    said anion exchange release resin:-   f) allowing said at least one release resin receptacle to release    water having a predetermined concentration of elemental iodine into    water from said water supply;-   h) using water having said predetermined concentration of iodine    water in the decontamination of consumables such as foodstuffs or in    installations using water reticulation such as swimming pools, water    supplies, cooling towers, water tanks, town water;-   i) converting iodide and iodine species to iodine at said conversion    station.    According to a preferred embodiment the method comprises the further    steps of-   j) recirculating water from said treatment station-   k) repeating steps (d)–(i).    Preferably said conversion step is effected at said conversion    station using an electrowinning process, a catalyst or chemical    process.

In another broad form according to the method aspect, the presentinvention comprises; a method for sanitizing water used in the washingof consumables such as foodstuffs and in installations using waterreticulation such as swimming pools, water supplies, cooling towers,water tanks, town water by flushing or washing with iodine enrichedwater; wherein a concentration of elemental iodine is maintained withina predetermined range in a water stream; the method comprising the stepsof:

-   a) placing a source of iodine intermediate a source of main water    supply and a treatment station fed by said main water supply:-   b) placing at least one receptacle for containing an anion exchange    release resin charged with a predetermined amount of elemental    iodine between said source of elemental iodine and said station;-   c) placing at least one further receptacle for holding an anion    exchange collection/ absorbing resin capable of collecting the    iodide created by the sanitization;-   d) passing water through said source of iodine for enriching said    main water supply prior to introducing water from said main water    supply into said at least one release resin receptacles:-   e) allowing said at least one release resin receptacle to release    water having a predetermined concentration of elemental iodine into    water from said water supply;-   f) passing water through said treatment station and using water    having said predetermined concentration of iodine water in the    decontamination of consumables such as foodstuffs or-   g) passing water with said predetermined concentration of iodine    through installations using water reticulation such as swimming    pools, water supplies, cooling towers, water tanks, town water.-   h) passing water exiting said treatment station through said anion    exchange collecting resin for collection of iodide and/or iodine    species:-   i) removing iodide and or iodide species from said resin;-   j) converting said collected iodide or iodine species to iodine    using an electrowinning process, a catalyst or chemical reactions.    According to a preferred embodiment the method comprises the further    steps of;-   k) recirculating water discharged from said collection resins    through said process.-   l) repeating steps (d)–(i)    According to a preferred embodiment, the method comprises the    further steps; of stripping iodide from said resin and recharging    said resin to its original condition and prior to stripping said    iodide from said resin, washing all organic matter dirt and foreign    chemicals and the like from the resin rich in iodide.

According to one embodiment, the method comprises the further steps; ofstripping iodide from said resin and recharging said resin to itsoriginal condition and converting the iodide to iodine using anelectrochemical electrolysis process capable of converting iodide toiodine; and prior to stripping said iodide from said resin, washing allorganic matter dirt and foreign chemicals and the like from the resinrich in iodide.

In another broad form according to the method aspect, the presentinvention comprises; a method for sanitizing water used in the washingof consumables such as foodstuffs and in installations using waterreticulation such as swimming pools, water supplies, cooling towers,water tanks, town water by flushing or washing with iodine enrichedwater: wherein a concentration of elemental iodine is maintained withina predetermined range in a water stream; the method comprising the stepsof:

-   a) providing a source of iodine intermediate a source of main water    supply and a treatment station fed by said main water supply:-   b) providing at least one receptacle for holding an anion exchange    collection resin capable of collecting iodide and or iodine species    created by the process and remaining in water exiting the said    treatment station;-   c) passing water from said treatment station through said anion    exchange collecting resins:-   d) passing water through said source of iodine for enriching said    main water supply prior to introducing water from said main water    supply into said treatment station;-   e) removing iodide and or iodide species from said resin;-   f) converting said collected iodide and/or or iodine species to    iodine using an electrowinning process, a catalyst or chemical    reactions.    According to a preferred embodiment the method comprises the further    steps of;-   g) recirculating water from said treatment reservoir;-   h) repeating steps (a)–(g).

In another broad form according to the method aspect, the presentinvention comprises; a method for sanitizing water having saidpredetermined concentration of iodine water in the decontamination ofconsumables such as foodstuffs and in installations using waterreticulation such as swimming pools, water supplies, cooling towers,water tanks, town water by washing with iodine enriched water wherein aconcentration of elemental iodine is maintained within a predeterminedrange in a water stream; the method comprising the steps of;

-   a) placing a source of iodine intermediate a source of main water    supply and a treatment station fed by said main water supply:-   b) passing water through said source of iodine for enriching said    main water supply;-   c) using water having said predetermined concentration of iodine    water in the decontamination of consumables such as foodstuffs or in    installations using water reticulation such as swimming pools, water    supplies, cooling towers, water tanks, town water;-   d) taking water from said treatment station and delivering it to a    conversion station wherein iodide and/or iodine species in said    water may be converted to iodine by an electrowinning process, a    catalyst or a chemical process.-   e) recirculating water from said conversion for reuse in    sanitization.

In an alternative form the present invention comprises:

a process for maintaining a concentration of elemental iodine within apredetermined range in a water stream used in a process for sanitizingwater in the decontamination of consumables such as foodstuffs and ininstallations using water reticulation such as swimming pools, watersupplies, cooling towers, water tanks, town water by flushing or washingwith water having said predetermined concentration of iodine;

wherein the process comprises: a water reticulation network including asource of main water supply for delivery to a treatment station: asource of iodine disposed intermediate said source of main water supplyand said treatment reservoir; at least one receptacle for holding ananion exchange release resin charged with a predetermined amount ofelemental iodine and disposed intermediate said source of iodine andsaid treatment station: wherein, effluent from said treatment station isin communication with an iodide/absorption collection resin whichreceives said effluent from said reservoir and prior to recirculationthrough said process; wherein said iodide collecting resin may beremoved from the system and stripped of collected iodide whereupon aresultant iodide solution is passed through a conversion station capableof conversion of iodide to iodine thereby providing an iodine richsolution for reuse in said primary process.

According to a preferred embodiment the conversion of iodide to iodineis effected by an electrowinning process, catalyst such as green sand ora chemical process.

Preferably, when said collecting resin is removed from said process itis taken to a laboratory/factory in which the conversion will takeplace.

In an alternative form the present invention comprises:

a process for maintaining a concentration of elemental iodine within apredetermined range in a water stream used in a process for sanitizingwater in the decontamination of consumables such as foodstuffs and ininstallations using water reticulation such as swimming pools, watersupplies, cooling towers, water tanks, town water by flushing or washingwith water having said predetermined concentration of iodine; whereinthe process comprises: a water reticulation network including a sourceof main water supply for delivery to a treatment station: a source ofiodine disposed intermediate said source of main water supply and saidtreatment reservoir; wherein, effluent from said treatment station is incommunication with an iodide/absorption collection resin which receivessaid effluent from said reservoir and prior to recirculation throughsaid process; wherein said iodide collecting resin may be removed fromthe system and stripped of collected iodide whereupon a resultant iodidesolution is passed through a conversion station capable of conversion ofiodide to iodine thereby providing an iodine rich solution for reuse insaid primary process.

According to a preferred embodiment the conversion of iodide to iodineis effected by an electrowinning process, catalyst such as green sand ora chemical process.

In an alternative form the present invention comprises:

a process for maintaining a concentration of elemental iodine within apredetermined range in a water stream used in a process for sanitizingwater in the decontamination of consumables such as foodstuffs and ininstallations using water reticulation such as swimming pools, watersupplies, cooling towers, water tanks, town water by flushing or washingwith water having said predetermined concentration of iodine; whereinthe process comprises: a water reticulation network including a sourceof main water supply for delivery to a treatment station: a source ofiodine disposed intermediate said source of main water supply and saidtreatment reservoir; wherein, effluent from said treatment station is incommunication with an in line conversion station capable of conversionof iodide to iodine thereby providing an iodine rich solution for reusein said sanitization process.

According to a preferred embodiment the conversion of iodide to iodineis effected by an electrowinning process, catalyst such as green sand ora chemical process.

In an alternative form the present invention comprises:

a process for maintaining a concentration of elemental iodine within apredetermined range in a water stream used in a process for sanitizingwater in the decontamination of consumables such as foodstuffs and ininstallations using water reticulation such as swimming pools, watersupplies, cooling towers, water tanks, town water by flushing or washingwith water having said predetermined concentration of iodine; whereinthe process comprises: a water reticulation network including a sourceof main water supply for delivery to a treatment station: a source ofiodine disposed intermediate said source of main water supply and saidtreatment reservoir; at least one receptacle for holding an anionexchange release resin charged with a predetermined amount of elementaliodine and disposed intermediate said source of iodine and saidtreatment station: wherein, effluent from said treatment station is incommunication with an in line conversion station capable of conversionof iodide to iodine thereby providing an iodine rich solution for reusein said primary process.

According to a preferred embodiment the conversion of iodide to iodineis effected by an electrowinning process, catalyst such as green sand ora chemical process.

In an alternative form the present invention comprises:

a process for maintaining a concentration of elemental iodine within apredetermined range in a water stream used in a process for sanitizingwater in the decontamination of consumables such as foodstuffs and ininstallations using water reticulation such as swimming pools, watersupplies, cooling towers, water tanks, town water by flushing or washingwith water having said predetermined concentration of iodine; whereinthe process comprises: a water reticulation network including a sourceof main water supply for delivery to a treatment station; a source ofiodine disposed intermediate said source of main water supply and saidtreatment reservoir; wherein, effluent from said treatment station is incommunication with an in line conversion station capable of conversionof iodide to iodine thereby providing an iodine rich solution for reusein said sanitizing process.

According to a preferred embodiment the conversion of iodide to iodineis effected by an electrowinning process, catalyst such as green sand,or a chemical process.

In an alternative form the present invention comprises:

a process for maintaining a concentration of elemental iodine within apredetermined range in a water stream used in a process for sanitizingwater in the decontamination of consumables such as foodstuffs and ininstallations using water reticulation such as swimming pools, watersupplies, cooling towers, water tanks, town water by flushing or washingwith water having said predetermined concentration of iodine; whereinthe process comprises: a water reticulation network including a sourceof main water supply for delivery to a treatment station; a source ofiodine disposed intermediate said source of main water supply and saidtreatment reservoir; at least one receptacle for holding an anionexchange release resin charged with a predetermined amount of elementaliodine and disposed intermediate said source of iodine and saidtreatment station; wherein, effluent from said treatment station is incommunication with an in line conversion station capable of conversionof iodide to iodine thereby providing an iodine rich solution for reusein said primary process.

According to a preferred embodiment the conversion of iodide to iodineis effected by an electrowinning process, catalyst such as green sand ora chemical process.

In another broad form, the present invention comprises:

-   a conversion process for conversion of iodide and/or iodine species    to iodine (I2) wherein said iodine species for conversion by said    conversion process are collected from an iodine purification    process, the process comprising;-   a source of water for one or more water consuming applications and    providing a water stream in said process;-   a delivery station intermediate said source of water and a treatment    station;-   a source of iodine at the delivery station and means to enable    release into said water stream of the iodine; wherein,-   said water is charged with a predetermined concentration of the    iodine;-   wherein release of said iodine into said water stream is maintained    at a predetermined concentration within a predetermined range in a    water stream fed by said water supply; wherein said predetermined    concentration of iodine provides a predetermined level of    purification of said water stream.

According to a preferred embodiment the conversion of iodide to iodineis effected by an electrowinning process, catalyst such as green sand ora chemical process.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described in more detail according topreferred but non limiting embodiments and with reference to theaccompanying illustrations wherein:

FIG. 1 shows a flow diagram of an iodine purification process accordingto one embodiment, wherein iodine or iodide or iodine species iscollected from a water stream by an absorbing resin and iodide isconverted off site by either an electrowinning process, a catalyst orother chemical conversion process for reuse in the purification process;

FIG. 2 shows a flow diagram of an iodine purification process accordingto one embodiment, wherein iodine or iodide or iodine species isconverted in line by either an electrowinning process, a catalyst,chemical or other conversion process for reuse in the purificationprocess;

FIG. 3 shows a flow diagram of an iodine purification process accordingto one embodiment, wherein iodine is delivered to a treatment stationvia an iodine release resin and surplus iodine or iodide or iodinespecies is collected from a water stream by an absorbing resin andiodide is converted off site by either an electrowinning process, acatalyst or other conversion process for reuse in the purificationprocess;

FIG. 4 shows a flow diagram of an iodine purification process accordingto one embodiment, wherein iodine is delivered to a treatment stationvia an iodine release resin and surplus iodine and/or iodide or iodinespecies is converted in line by either an electrowinning process, acatalyst or other conversion process for reuse in the purificationprocess.

The invention will be described according to various embodiments asapplied in a treatment process using a reservoir or wash tank. It willbe appreciated by persons skilled in the art that the process accordingto alternative embodiments is also adaptable to water reticulationnetworks, cooling towers, swimming pools and other water consumingappliances.

Referring to FIG. 1 there is shown an iodine based purification processfor sanitizing consumables such as food stuffs by washing in a waterstream. The process is adaptable to water reticulation systems, such ascooling towers, swimming pools and water consuming appliances. Theprocess will principally be described with reference to its applicationto food sanitization in a reservoir. According to one embodiment theprocess comprises a source of water indicated by arrow 1 which wouldpreferably be delivered from a mains supply or self contained supplysuch as a gravity feed reservoir. The process optionally comprises acirculating pump 2, and an optional filter 3 located upstream of aniodine crystals canister/s 4. One or a plurality of canisters may beused depending upon process requirements. Canisters 4 receive water viawater stream 22 and discharge water via flow line 17 and 18 to mainwater supply flow line 21. Flow line 21 is in communication with atreatment station 5 which may be a reservoir. Canisters 4 each compriseiodine crystals and supply the water supply line 21 via lines 17 and 18with a saturated iodine solution. An iodinated solution from iodinecanister 4 is delivered via lines 17 and 18 to reservoir 5 in whichbiocidal treatment of consumables such as foodstuffs may take place.Water exiting reservoir 5 is directed along a flow line represented byarrow 6 where it enters iodine absorption resin canisters 7 and 8.Iodine absorption canisters 7 and 8 recover iodide from water stream 6following which water effluent from canister 7 and 8 is eitherrecirculated through the process via a water stream indicated by arrows9 and 10 or discharged to waste via a water stream indicated by arrow11.

According to the embodiment of FIG. 1, iodine absorption canisters 7 and8 are taken off site whereupon the collected iodide or iodine speciesundergoes conversion at a conversion station 12. The conversion may takeplace using a conversion process which may be selected from anelectrowinning process 13, a catalyst conversion process 14 oralternative process 15 such as use of conventional chemical reactionsemploying known oxidants. Iodine produced by those processes may becollected in collection tank 16 for later reuse in the sanitizationprocess.

The catalyst process 14 is capable of converting iodide to iodine byoxidation using air at ambient temperatures. The catalyst used ispreferably green sand although it will be appreciated that othersuitable catalysts may be used in the conversion of iodide to iodine.

According to one embodiment, the system is adapted for recirculationsuch that water exiting the treatment reservoir is eventuallyreintroduced into the sanitization process once it has exited absorptionresin canisters 7 and 8. Recirculated water may be passed through theiodine canisters 4 where the water will be enriched with iodine. Waterrich in iodine will be delivered via flow line 17 and 18 to flow line 21and to treatment reservoir 5 as previously described.

Referring to FIG. 2 there is shown an alternative iodine basedpurification process for sanitizing consumables such as food stuffs bywashing in a water stream. The process which is a variation of theprocess described in FIG. 1 is also adaptable to water reticulationsystems, such as cooling towers, swimming pools and water consumingappliances. According to one embodiment the process comprises a sourceof water indicated by arrow 1 which would preferably be delivered from amains supply or self contained supply such as a gravity feed reservoir.The process optionally comprises a circulating pump 2, and an optionalfilter 3 located upstream of an iodine crystals canister 4. One or aplurality of canisters may be used depending upon process requirements.Canisters 4 receive water via water stream 22 and discharge water viaflow line 17 and 18 to main water supply flow line 21. Flow line 21 isin communication with a treatment station 5 which may be a reservoir.Canisters 4 each comprise iodine crystals and supply the water supplyline 21 via lines 17 and 18 with a saturated iodine solution. Aniodinated solution from iodine canister 4 is delivered via line 17 and18 to engage flow line 21. As before, the canisters each comprise iodinecrystals and supplies the water supply line 17 with a saturated iodinesolution. Water is delivered to reservoir 5 in which biocidal treatmentof consumables may take place. Water exiting reservoir 5 is directedalong a path represented by arrow 6 where it enters in line conversionstation 12. A conversion process may be selected from an electrowinningprocess 13, a catalyst conversion process 14 or alternative process 15such as conventional chemical reactions using known oxidants. Iodineenriched water produced by those processes is reintroduced into thesanitization process via water stream indicated by arrows 9 and 10.

The catalyst process 14 is according to the FIG. 2 embodiment capable ofconverting iodide to iodine by oxidation using air at ambienttemperatures. The catalyst used is preferably green sand although itwill be appreciated that other suitable catalysts may be used in theconversion of iodide to iodine.

The process is adapted for recirculation such that water exiting thetreatment reservoir 5 is eventually reintroduced into the processpreferably via conversion station 12 upstream of the filter 3 whichfilters out any impurities. Water rich in iodine will be delivered totreatment reservoir 5 via iodine crystals canister 4 and flow line 17,18 and 21.

Referring to FIG. 3 there is shown an iodine based purification processsubstantially the same as the process described in FIG. 1, forsanitizing consumables such as food stuffs by washing in a water stream.The process comprises a source of water indicated by arrow 1 which wouldpreferably be delivered from a mains supply or self contained supplysuch as a gravity feed reservoir. The process optionally comprises acirculating pump 2, and an optional filter 3 located upstream of aniodine crystals canister 4. One or a plurality of canisters may be useddepending upon process requirements. Canisters 4 are in indirectcommunication with a treatment station 5. Canisters 4 receive water viawater stream 22 and discharge water via flow line 17 and 18 to mainwater supply flow line 21. Flow line 21 is in communication with iodinerelease resins 19 and 20. Water passes through release resins 19 and 20prior to entry into reservoir 5 thereby supplementing iodine deliveredto the process from canister 4. The iodinated solution from iodinecanister 4 delivered via lines 17 and 18 to reservoir 5 may be employedin biocidal treatment of consumables such as foodstuffs. Water exitingreservoir 5 is directed along a path represented by arrow 6 as beforewhere it enters iodine absorption resin canisters 7 and 8. The remainderof the process is as described for the embodiment of FIG. 1. As with theembodiment of FIG. 1 once iodide and other iodine species are collectedby collection resins 7 and 8 the water stream may be recirculated ordumped to waste depending upon process requirements.

Referring to FIG. 4 there is shown an alternative iodine basedpurification process for sanitizing consumables such as foodstuffs bywashing in a water stream. The process which is a variation of theprocess described in FIG. 2 is also adaptable to water reticulationsystems, such as cooling towers, swimming pools and water consumingappliances. According to one embodiment the process comprises a sourceof water indicated by arrow 1 which would preferably be delivered from amains supply or self contained supply such as a gravity feed reservoir.The process optionally comprises a circulating pump 2, and an optionalfilter 3 located upstream of an iodine crystals canisters 4. One or aplurality of canisters may be used depending upon process requirements.Canisters 4 are in indirect communication with a treatment reservoir 5.Canisters 4 receive water via water stream 22 and discharge water viaflow lines 17 and 18 to main water supply flow line 21. Flow line 21 isin communication with iodine release resins 19 and 20. Water passesthrough release resins 19 and 20 prior to entry into reservoir 5 therebysupplementing iodine delivered to the process from canister 4. As beforethe canisters each comprise iodine crystals and supplies the watersupply with a saturated iodine solution. Water exiting reservoir 5 isdirected along a path represented by arrow 6 where it enters in lineconversion station 12. The remainder of the process is as described forthe embodiment of FIG. 2.

The catalyst process 14 is according to the FIG. 2 embodiment capable ofconverting iodide to iodine by oxidation using air at ambienttemperatures. The catalyst used is preferably green sand although itwill be appreciated that other suitable catalysts may be used in theconversion of iodide to iodine.

The process is adapted for recirculation such that water exiting thetreatment reservoir 5 is eventually reintroduced into the process viaconversion station 12 upstream of the filter 3 which filters out anyimpurities. Water rich in iodine will again be delivered to treatmentreservoir 5 via iodine crystals canister 4 and release resins aspreviously described.

In each of the embodiments described iodine canisters 4 will receivewater from the main supply system which will mix with a high surfacearea fast dissolving iodine specie held in the iodine canisters. Thereis a controlled release of iodine species by use of such means as acontrol valve.

According to the embodiments of the process of FIGS. 3 and 4, the iodinesupply canister/s 4 may be disposed in series or parallel with resinbeds 19 and 20 and water recharges the resin bed with iodine solution.In each of the embodiments of the process described, the iodine canisterwill preferably be activated when the resin beds require recharging andthis will be measured by flow of water or by iodine residual. The flowof water exiting filter 3 may be directed along the path represented byarrow 21 where the resin beds in canisters 19 and 20 are not in need ofrecharging. When resin beds 19 and 20 require recharging with apredetermined proportion of water delivered in the direction of arrow 22so that it passes through iodine canister/s 4 via lines 17 and 18 priorto entering main water flow line 21 and prior to entry into releaseresins 19 and 20.

In the case of the embodiments of FIGS. 3 and 4, the iodine releaseresin beds in canister 19 and 20 will each contain a suitable amount ofanion exchange resin suitably charged with elemental iodine to apredetermined level. The anion exchange resins will release water withan iodine concentration of between 0.5 and 100 parts per million ofelemental iodine into the main water flow. The iodine enriched productmay be then used as a treatment in such applications as biocidaltreatment of consumables such as food products introduced into reservoir5 for sanitizing.

This is a cost effective and efficient way of ensuring that the levelsof iodine are maintained at an acceptable and measurable level throughthe sanitizing process.

According to the embodiments of FIGS. 2 and 4, where a catalyst isselected for use at conversion station 12 the catalyst converts iodideto iodine at ambient temperatures using air as the oxidant. The iodinerich solution is then recycled back into the sanitizing process aspreviously described. According to one embodiment the catalyst may begreen sand.

More than one resin may share the same canister. According to theembodiments of FIGS. 1 and 3 iodide absorbing resins when removed fromthe process for off site processing are stripped of iodide. The resin iswashed of all foreign matter including chemicals, dirt and organicmatter leaving an exchange resin rich in iodide. The iodide is strippedfrom the resin and the resin is recharged to its original condition. Theiodide may be converted to iodine using an electrochemical electrolysisprocess, a catalyst, conventional chemical reactions or other conversionoption.

In an alternative embodiment, the iodine delivery step may be initiatedfrom a remote location. For instance a remote computer may monitoriodine, iodide or iodine species levels and adjust the delivery ofiodine according to process requirements. In addition, the sanitizationprocesses may be supplemented with iodine delivered from a remotelocation. In this embodiment, iodine canisters may be located remotefrom the process, whereupon a controlled delivery of the iodine may beeffected by a PLC once process performance data and parameters which maybe determined via probes, have been down loaded into the computer.

Test Results

By way of example, simulation tests were conducted to determine theefficacy of the process and methodology of the invention applied to foodsanitization and more particularly to determine if use of a controlleddelivery of iodine into a wash solution at predetermined concentrationswould result in effective sanitization of fruits and vegetables.

The process and method of the invention described herein according toits various forms provide a capability for delivery of preciselycontrollable levels of iodine, which can, if appropriately used,overcome the problems caused by the use of chlorine in wash water.

This study intended to examine the efficacy of iodine as a sanitizer asapplied by the controlled process of the invention described herein. Theefficacy tests for iodine have been evaluated by analysing for totalbacteria and fungal counts found on the surfaces of fruits andvegetables. Some of the organisms found on the surfaces of fruits andvegetables are harmful (or pathogenic) to humans and some are harmfuland pathogenic to the fruits and vegetables. Reducing significantly thebackground levels of bacteria and fungi on fruit and vegetables willhave beneficial effects on both the safety of eating the sanitised foodand shelf life of the foodstuff.

Representative fruits and vegetables were chosen from each of the majorcategories of fruits and vegetables. While the basic efficacy data wasobtained with clean water, tests were also carried out for efficacy ofiodine on fruits and vegetables in presence of dirt. Dirt would normallybe found in any commercial treatment situation. The time used fordipping was typically one minute, however, efficacy as a consequence ofvarying the time of dipping was also studied.

Materials and Methods

Post harvest dipping trials were conducted with iodine solutions, alongwith a chlorine solution, for washing freshly harvested fruits andvegetables to control natural organisms on the surface of the produces.The germicidal effect of iodine was examined by dipping the produce in anumber of different ways as described below.

Source and Quality of Fruit and Vegetables

All the fruit and vegetables used in the experiments were obtaineddirectly from growers. No washing or cleaning of any type was done onthe produce. This meant that the bacteria and fungi were a typicalrepresentation of normal levels present when the produce comes into thepacking shed for treatment and packing.

A. Tests with Laboratory Dipping

Efficacy tests of elemental iodine at a range of concentrations wereperformed in 5 to 10 L containers in the laboratory. With carefuladjustment of levels and only a small number of samples being used foreach freshly prepared dip, this method was used for oranges, potatoes,peaches, nectarines, tomatoes, lettuce and bean sprouts.

Fruits and vegetables (orange, apple, peach, nectarine and tomato) weredipped for 1 min taking 10 fruits at a time in 5–10 L of solution of setconcentrations. For lettuce a total of 5 outer leaves were takenrandomly from different heads and dipped in 5 L of water for 1 min. Forbean sprouts, 5 perforated bags of bean sprouts each containing about120 g of sprouts were dipped in fresh solutions.

B. Tests Performed with an Iodine Sanitizer Unit According to theInvention

These tests were performed using an iodine sanitizer unit. Dip levels of150 L of iodine solutions were used in the treatment tank, with overallsystem flow rates of 30 or 60 L/min. The iodine unit was adjusted to therequired concentration by adjusting the proportion of the flow goingthrough an iodine delivery canister. Once this was done, the unit keptthe iodine concentration at a constant level, with continuous rechargingof iodine in the treatment tank to keep a constant concentration.

Crops tested with this unit were apples, avocadoes, potatoes, lettuce,strawberries and rockmelons.

In the iodine unit, 15 fruits/tubers of apple, potato and avocado, 30strawberries, 6 rockmelons and 6 heads of lettuce were dipped in the(150 L) tank of iodine solutions for 1 min. For chlorine dip, 25 Lsolutions at 30 ppm were used for dipping the same number offruits/tubers. The water control treatment was dipped in fresh water inthe iodine unit tank with continuous circulation through pump.

C. Dipping Time

The effect of dip timing on efficacy test of iodine and chlorine wasexamined. Crops tested were potatoes at 30 ppm and oranges at 3.3 ppm ofiodine and chlorine. In these experiments the produces were dipped for1, 2 and 4 min for the efficacy of the chemicals. Dippings were done ina 5–10 L container at a set concentration as above.

D. Dirt Effects

Effects of dirt on efficacy of iodine and chlorine on tomato and appleusing the sanitiser unit according to the invention at 30 L min.

For the test of the influence of dirt on iodine and chlorine efficacy onfruits and vegetables, an amount of dirt and organic material (clay loamsoil and broccoli puree at a concentration of 0.5% of weight to dipvolume) was added to dip tank in two installments 30 min apart. Thewater in the tank was circulated continuously through the filter of theiodine unit, which over time trapped more and more of the dirt. Theproduce wag dipped in the treatment tank solution in at 0 min (beforedirt), 5, 20 and 50 min from the start of the experiment.

E. Residues

Residual Effect of Iodine on Orange Potato, Peach, Nectarine and Tomato.

Fruits and vegetables were dipped in 30 and 60 ppm of solution and thesamples for iodine assessment were taken 3–6 hours after dipping and 3days after dipping. The amount of iodine and iodide residues on fruitsand vegetables were assessed following the ‘method of analysis fordetermination of total iodine in foods’ as recommended by NationalHealth and Medical Research Council (June, 1986).

Total Bacteria and Total Fungal Testing

Efficiency of the chemicals was studied by observing the killing ratesof naturally occurring surface organisms on fruits and vegetables. Afterdipping in chemicals, fruits and vegetables were allowed to air dry fora minimum of three hours before taking samples for counting thepopulation of the organisms. The samples from the smooth or semi-smoothsurface of fruits and vegetables were collected by cleaning a 9 cm² areaon the surface with a wet, sterile cotton bud. The cotton bud was thenplaced in a vial with 10 ml of sterile water. Fruits or vegetables withrough surface like strawberry and rockmelon, the whole fruit(strawberry) or a cut portion of rockmelon skin (20 cm²) were shaken ina stomaching bag with 50–70 mls of 1% peptone solution and then takenabout 10 ml of sample for counting the organisms. For each treatment asample was taken from each of the 5 different fruits/vegetables. Thesesamples were then used for counting the bacteria and fungal coloniesafter culturing dilutions on NA or PDA culture media. Samples (0.25 ml)from the dilutions were spread on NA plates in duplicate and incubatedat 20–25 degrees C. for 2–3 days before counting the number of colonies.The number of bacteria and fungal colonies were then calculated per cm²of the surface area and converted to log₁₀ values.

RESULTS

Besides being expressed as total count per cm², the results wereconverted to log10 units as is commonly used in food microbiology. Theefficacy of the chemicals are also indicated by the log₁₀ reductionvalue, with the reduction made in comparison with the undipped controltreatment. This was used rather than the dipped control because thewater used in the dipped control especially of the 150 L treatment tank,may contain traces of chlorine and therefore not give a true ‘control’value.

The following tables provide results of chemical treatments on selectedfruits and compares iodine treatment to chlorine.

Peach (Lab Dipped)

TABLE 1 Bacterial population per cm² Fungal population per cm² ChemicalActual Log₁₀ Log₁₀ Actual Log₁₀ Log₁₀ treatments count count reductioncount count reduction Control 2170 3.31 0.00 a* 185 2.26 0.00 a*(undipped) Control 1054 3.01 0.30 ab 128 2.09 0.16 ab (dipped) Iodine 469 2.65 0.66 b  66 1.81 0.45 ab 3.3 ppm Iodine  83 1.9 1.41 c  17 1.001.26 c 10 ppm Iodine   8.5 0.41 2.90 e  2.3 0.23 2.03 d 30 ppm Chlorine 79 0.85 2.46 de  3.2 0.29 1.97 d 30 ppm *Means followed by differentletters are significantly different (k LSD test)

Iodine increased in effectiveness up to 30 ppm, with a similar patternfor bacteria and fungi. Log10 reductions of greater than 2 show iodinebeing very effective at 30 ppm against both bacteria and fungi.Bacterial control by iodine was more effective than fungal control byiodine. There was a major increase in effectiveness going from 10 to 30ppm. Iodine was more effective than chlorine for bacteria (with 10 ppmiodine being equal to 30 ppm chlorine) than for fungi.

Potato (Sanitizing Unit)

TABLE 2 Bacterial population per cm² Fungal population per cm² ChemicalActual Log₁₀ Log₁₀ Actual Log₁₀ Log₁₀ treatments count count reductioncount count reduction Control 906 2.92 0.00 a* 127 2.03 0.00 a(undipped) Control 716 2.82 0.10 a  20 1.28 0.79 b (dipped) Iodine 3702.54 0.39 ab  2 0.07 1.96 d 10 ppm Iodine 260 2.34 0.58 b  3 0.04 1.99 d20 ppm Iodine 249 2.38 0.54 b  3 0.40 1.63 cd 30 ppm Chlorine 378 2.560.38 ab  4 0.62 1.46 c 30 ppm *Means followed by different letters aresignificantly different (k LSD test)

Iodine was of limited effectiveness against bacteria. The effectivenesswas greater against fungi this time, with good log10 reduction between1.5 and 2 for concentrations between 10 and 30 ppm. There was no greatercontrol as concentration increased for 10 to 30 ppm. Fungal control byiodine was more effective than bacterial control. The increasedeffectiveness against fungi in this experiment is believed to be due tothe more effective delivery of iodine by the Sanitising Unit accordingto the invention. Fungi are a more serious cause of the loss of keepingquality on potatoes under most conditions than bacteria, so iodinetreatment would be effective for potatoes.

Lettuce (Sanitizing Unit)

TABLE 3 Bacterial population per cm² Fungal population per cm² ChemicalActual Log₁₀ Log₁₀ Actual Log₁₀ Log₁₀ treatments count count reductioncount count reduction Control 3077 3.39 0.00 a* 20   1.32 0.00 a(undipped) Control 1261 3.06 0.33 a 14   1.04 0.28 a (dipped) Iodine 130 2.03 1.36 b  1.03 −0.12 1.44 bc 10 ppm Iodine  79 1.64 1.74 bc 0.44 −0.35 1.67 bc 20 ppm Iodine  38 1.51 1.89 c  0.44 −0.35 1.67 bc 30ppm Chlorine  14 0.71 2.11 d  0.44 −0.35 1.67 bc 30 ppm *Means followedby different letters are significantly different (k LSD test)

Iodine increased in effectiveness up to 30 ppm, with a similar patternfor bacteria and fungi. Log10 reductions of greater than 1.5 show iodinebeing effective at 20 and 30 ppm against fungi. Bacterial control byiodine was more effective than fungal control. There was a majorincrease in effectiveness going from 10 to 30 ppm. Chlorine was moreeffective than iodine for bacteria. Iodine was equivalent ineffectiveness to chlorine for fungi.

The Iodine Sanitizer Unit according to the embodiments of the inventiondescribed and with their constant delivery resulted in largeimprovements in effectiveness compared to laboratory dipping.

Apple (Iodine Sanitization Unit)

TABLE 4 Bacterial population per cm² Fungal population per cm² ChemicalActual Log₁₀ Log₁₀ Actual Log₁₀ Log₁₀ treatments count count reductioncount count reduction Control 160   2.14 0.00 a* 104   1.99 0.00 a(undipped) Control  93   1.95 0.20 a  60   1.70 0.29 a (dipped) Iodine 10   0.20 1.94 b  3.2 −0.56 2.55 bc 10 ppm Iodine  6.7   0.086 2.05 b 1.8 −0.37 2.36 bc 20 ppm Iodine  1.4 −0.40 2.54 bc  0.1 −1.00 2.99 c 30ppm Chlorine  4.0   0.28 1.86 b  1.8 −0.13 2.12 b 30 ppm *Means followedby different letters are significantly different (k LSD test)

Iodine increased in effectiveness up to 30 ppm, with a similar patternfor bacteria and fungi. Log10 reductions of greater than 2 show iodinebeing very effective at 30 ppm against both bacteria and fungi. Fungalcontrol by iodine was more effective than bacterial control. There was amajor increase in effectiveness going from 10 to 30 ppm. Iodine wasconsiderably more effective than chlorine for bacteria and fungi. Whilethe effectiveness is greatest at 30 ppm, iodine is so effective againstapples that 20 ppm is still very effective, especially for fungi whichare a bigger problem for keeping quality.

Strawberry (Sanitization Unit)

TABLE 5 Bacterial population per cm² Fungal population per cm² ChemicalActual Log₁₀ Log₁₀ Actual Log₁₀ Log₁₀ treatments count count reductioncount count reduction Control 16405 4.19 0.00 a* 878 2.93 0.00 a(undipped) Control 10550 3.96 0.23 ab 864 2.87 0.057 a (dipped) Iodine 4230 3.62 0.57 bc 115 1.97 0.95 cd 10 ppm Iodine  3443 3.52 0.67 bcd 71 1.83 1.10 d 20 ppm Iodine  2085 3.19 1.01 cd  39 1.03 1.90 e 30 ppmChlorine  3710 3.53 0.66 bcd 519 2.62 0.31 a 30 ppm *Means followed bydifferent letters are significantly different (k LSD test)

Iodine is of lower effectiveness for bacteria, but gives good controlagainst fungi at higher concentrations. Log10 reductions of almost 2 forfungi shows that iodine gives very significant control at 30 ppm. Fungalcontrol by iodine was considerably more effective than bacterial controlby iodine. There was only a slight increase in effectiveness going from10 to 30 ppm. Iodine was considerably more effective than chlorine forbacteria and fungi, with levels of 10 ppm iodine being more effectivethan 30 ppm chlorine.

Avocado (Sanitization Unit)

TABLE 6 Bacterial population per cm² Fungal population per cm² ChemicalActual Log₁₀ Log₁₀ Actual Log₁₀ Log₁₀ treatments count count reductioncount count reduction Control 843 2.92 0.00 a* 121 2.05 0.00 a(undipped) Control 571 2.74 0.17 a  72 1.84 0.21 a (dipped) Iodine  221.27 1.64 d  13 1.10 0.96 b 10 ppm Iodine  14 1.02 1.90 de  7.6 0.541.51 cd 20 ppm Iodine  6.6 0.72 2.19 e  3.1 0.26 1.79 de 30 ppm Chlorine 23 1.22 1.70 d  9.3 0.94 1.11 bc 30 ppm *Means followed by differentletters are significantly different (k LSD test)

Iodine increased in effectiveness up to 30 ppm, with a similar patternfor both bacteria and fungi. Log10 reductions of greater than 1.5 showiodine being effective at 30 ppm against both bacteria and fungi.Bacterial control and fungal control by iodine was similar. There was amajor increase in effectiveness going from 10 to 30 ppm. Iodine was moreeffective than chlorine for bacteria (with 10 ppm iodine being equal to30 ppm chlorine), it was similarly more effective for fungi.

Rockmelon (Sanitization Unit)

TABLE 7 Bacterial population per cm² Fungal population per cm² ChemicalActual Log₁₀ Log₁₀ Actual Log₁₀ Log₁₀ treatments count count reductioncount count reduction Control 124,380 5.09 0.00 a* 750   2.86 0.00 a(undipped) Control  94,827 4.97 0.12 a 493   2.60 0.25 a (dipped) Iodine 19,514 4.26 0.83 b  55   1.55 1.31 d 10 ppm Iodine  14,456 4.15 0.93 bc 0.80 −0.10 2.95 e 20 ppm Iodine  10,028 3.98 1.10 cd  0.80 −0.10 2.95 e30 ppm Chlorine  10,752 4.03 1.06 bcd  0.80 −0.10 2.95 e 30 ppm *Meansfollowed by different letters are significantly different (k LSD test)

There was only moderate activity of iodine against bacteria, however,the levels of background bacteria were extremely high. For more normalbackground levels of fungi, excellent control was found by iodine, withno extra benefit in efficacy found going from 20 to 30 ppm. Log10reductions of considerably more than 2 show iodine being very effectiveat 20 and 30 ppm against fungi. Fungal control by iodine was moreeffective than bacterial control. Iodine was of equivalent effectivenessto chlorine for both bacteria and fungi.

Tomato with Dirt (Sanitization Unit)

TABLE 8 Bacterial population per cm² Fungal population per cm² ChemicalActual Log₁₀ Log₁₀ Actual Log₁₀ Log₁₀ treatments count count reductioncount count reduction Control 117 2.08 0.00 a* 36   1.57 0.00 a Iodine 9 0.95 1.17 efgh  2.7   0.11 1.46 hi (20 ppm) 0 min Iodine  47 1.670.41 abc  1.6 −0.12 1.68 i 5 min Iodine  21 1.32 0.77 cde  3.8   0.531.04 defgh 20 min Iodine  22 1.33 0.75 cde  3   0.13 1.45 ghi 50 minChlorine  12 0.98 1.03 defg  3   0.23 1.34 fghi (30 ppm) 0 min Chlorine 15 1.17 0.92 def  4.7   0.62 0.94 def 5 min Chlorine  23 1.38 0.74 cd 9   0.86 0.71 cd 20 min Chlorine  36 1.56 0.46 bc 25   1.30 0.26 ab 50min *Means followed by different letters are significantly different (kLSD test)

The initial level of iodine (20 ppm) and chlorine (30 ppm) used in thedip gave a reduction of bacteria and fungi by about 1 log₁₀ units. Theaddition of dirt and broccoli puree raises the level of bacteria on thesurface of the tomatoes, despite the presence of sanitizers in the dip.This is because high levels of bacteria were present in the added dirtand these raised levels were transferred to the surface of the tomatoes.After 5 min of adding dirt, iodine was less active than that of chlorineagainst bacteria, but was more active against fungi. As iodine wasrecharging into the tank at its set concentration, it reactivated overtime and showed increased effectiveness in controlling the organisms inthe later treatments. On the contrary, chlorine was not recharging andits concentration was reducing over time after addition of dirt andreduced the effectiveness against the organisms. Over time, and as dirtlevels build in the dip, iodine becomes more and more effective incomparison to chlorine.

Apple with Dirt (Sanitization Unit)

TABLE 9 Bacterial population per cm² Fungal population per cm² ChemicalActual Log₁₀ Log₁₀ Actual Log₁₀ Log₁₀ treatments count count reductioncount count reduction Control 126 2.01 0.00 a* 59   1.73 0.00 a Iodine 5 0.31 1.71 fg  0.44 −0.35 2.09 g 0 min Iodine  60 1.74 0.28 a  0.8−0.21 1.95 g 5 min Iodine  6 0.73 1.29 cdcf  4   0.47 1.27 cdef 20 minIodine  5 0.48 1.53 defg  5   0.12 1.62 ef 50 min Chlorine  3 0.25 1.77fg  3   0.20 1.53 defg 0 min Chlorine  26 1.03 0.99 bcd  7   0.60 1.14cde 5 min Chlorine  22 1.07 0.94 bc  6   0.67 1.07 bcde 20 min Chlorine 56 1.69 0.33 a 19   1.22 0.52 ab 50 min *Means followed by differentletters are significantly different (k LSD test)

The initial level of iodine and chlorine in the dip gave a reduction ofbacteria and fungi by about 1.5 log₁₀ units. It is noticeable that theaddition of dirt and broccoli puree raises the level of bacteria on thesurface of the apples. This is because high levels of bacteria werepresent in the added dirt and these higher levels were transferred tothe surface of the apples. After 5 min of adding dirt, iodine was lessactive than that of chlorine against bacteria, but was found to be moreactive against fungi. As iodine was recharging into the tank at its setconcentration (20 ppm), it reactivated over time and showed increasedeffectiveness in controlling the organisms in the later treatments. Onthe contrary, chlorine was not recharging and its concentration wasreducing over time after addition of dirt and reduced the effectivenessagainst the organisms. Over time, and as dirt levels build in the dip,iodine becomes more and more effective in comparison to chlorine.

These results clearly show the efficacy of iodine as a sanitiser againstbacteria and fungi found on fresh fruit and vegetables (see SummaryTable below).

Application of iodine by the Iodine Sanitizer Unit was found to beconsiderably more effective than using an iodine dip. Over the range ofproducts and concentrations used, iodine was found to be considerablymore effective than an equivalent concentration of chlorine. This isparticularly so if the iodine was added with the Iodine Sanitizer Unit.

With some crops, iodine controlled bacteria best and with other crops itcontrolled fungi best. It seems the ISU especially assists with iodinecontrol against fungi. The required concentration to give a very goodreduction in bacteria or fungi of 1.5 log₁₀ (or a 30 fold reduction inconcentration) varied considerably from crop to crop and suggests thatdifferent concentrations should be recommended for different types ofcrops.

Summary Table of Efficacy Results

Fungi—dose for Better Control of Bacteria—dose for ~1.5 log₁₀ Bettercontrol by iodine/ Crop Bacteria/Fungi ~1.5 log₁₀ reduction reductionchlorine Orange (L)* Bacteria 30 30 Chlorine Nectarine (L)* Bacteria 3.310 Iodine Peach (L)* Bacteria 10 30 Iodine Potato (L)* Fungi >30 >30Iodine Potato (ISU) Fungi >30 10 Iodine Tomato (L) Fungi 20 20 IodineLettuce (L) Bacteria 30 >30 Chlorine Lettuce (ISU) Fungi 20 10 IodineBean sprouts (ISU) — 30 30 Iodine Apples (ISU) Fungi 10 10 IodineStrawberry (ISU) Fungi >30 30 Iodine Avocado (ISU) Bacteria 10 20 IodineRockmelon (ISU) Fungi >30 20 Same effectiveness *Concentrations of 3, 10& 30 used rather than 10, 20, 30 ppm iodine.

The effect of adding high levels of dirt to both the iodine and chlorinedips in a recirculating mode demonstrated that as dirt levels and timeof dip usage increased, the Iodine Sanitizer Unit was considerablysuperior to chlorine. The results also demonstrated that increasing thedip concentration using iodine dips from one to four minutes wasequivalent in effectiveness to doubling the dip concentration.

It will be recognised by persons skilled in the art that numerousvariations and modifications may be made to the invention as broadlydescribed herein such as but not limited to use of substitutes for theresins without departing from the overall spirit and scope of theinvention.

1. An apparatus for iodine decontamination and purification of a waterstream, the apparatus comprising: a source of water for one or morewater consuming applications and for providing a water stream; adelivery station intermediate said source of water and a treatmentstation; a source of iodine at the delivery station; means to enablerelease into said water stream of said iodine; a monitoring electrodeassociated with the delivery station which maintains the iodine in saidwater stream at a predetermined concentration to provide a predeterminedlevel of purification of said water stream and/or objects in contactwith said water stream in the treatment station; means for recovery fromsaid water stream of said iodine and/or iodide and/or other iodinespecies derived from said iodine; and means for conversion of all saidrecovered iodine species derived from said iodine delivered to saidstream to iodine as used in this system.
 2. An apparatus according toclaim 1, further including a controller which receives a signal from themonitoring electrode relating to the actual concentration of iodine inthe water stream which compares iodine concentration in the water streamwith said predetermined concentration.
 3. An apparatus according toclaim 2, wherein the controller is a computer which enables controlledrelease of iodine from said delivery station when said iodine fallsbelow the predetermined concentration.
 4. An apparatus according toclaim 3, wherein the electrode is iodine specific.
 5. An apparatusaccording to claim 3, wherein said computer prevents delivery of saidiodine from the delivery station when the iodine concentration reachesthe predetermined concentration.
 6. An apparatus according to claims 1or 5, further comprising an iodide/absorption collection resin whichreceives effluent from said treatment station and which recovers iodidefrom said effluent.
 7. An apparatus according to claim 1, wherein saidconversion means comprises electrowinning means to convert said iodinespecies to iodine.
 8. An apparatus according to claim 1, wherein saidconversion means employs green sand as a catalyst.
 9. An apparatusaccording to claim 1, wherein said conversion means employs a chemicalprocess using chemical oxidants.
 10. An apparatus according to claim 9,wherein said chemical oxidants are selected from permanganate,dichromate, hydrogen peroxide, bromate, iodate, chlorate, cerium,copper, chlorine and bromine.
 11. An apparatus for maintaining aconcentration of elemental iodine within a predetermined range in awater stream used in a sanitizing process for the decontamination ofconsumables such as foodstuffs and of installations using waterreticulation such as waste water, swimming pools, water supplies,cooling towers, water tanks, town water by flushing or washing withwater having said predetermined concentration of iodine; said apparatuscomprising: a water reticulation network including a source of water, adelivery station and a treatment station; a source of iodine disposedintermediate said source of water and said treatment station; anelectrode to control release of iodine into said water stream such thatthe iodine is maintained at a predetermined concentration so that theconcentration of iodine provides a predetermined level of purificationof said water stream or objects introduced into said water stream; andconversion means capable of conversion of iodide to iodine therebyproviding an iodine rich solution for reuse in a process incommunication with effluent from said treatment station.
 12. Anapparatus according to claim 11, wherein the electrode sends a signalrelating to the actual concentration of iodine in the water stream to acontroller which compares iodine concentration in the water stream withsaid predetermined concentration.
 13. An apparatus according to claim12, wherein the controller is a computer which enables controlledrelease of iodine from said delivery station when said iodine fallsbelow the predetermined concentration.
 14. An apparatus according toclaim 12, wherein said controller releases a predetermined concentrationof iodine into the water stream proportionate to a level ofcontamination of said water stream or objects in contact with the waterstream in the treatment station.
 15. An apparatus according to claim 12,wherein said controller maintains the iodine concentration in the flowstream irrespective of the flow rate, temperature of the water streamand level of contamination of said water or objects in contact with thewater stream in the treatment station.
 16. An apparatus according toclaim 11, wherein said conversion means comprises electrowinning means.17. An apparatus according to claim 11, wherein the electrode is iodinespecific.
 18. An apparatus for maintaining a concentration of elementaliodine within a predetermined range in a water stream used in a processfor sanitizing water or in the decontamination of consumables such asfoodstuffs and in installations using water reticulation such as wastewater, swimming pools, water supplies, cooling towers, water tanks ortown water by flushing or washing with water having said predeterminedconcentration of iodine; wherein the apparatus comprises: a waterreticulation network including a source of main water supply fordelivery to a treatment station; a source of iodine disposedintermediate said source of main water supply and said treatmentstation; at least one receptacle for holding elemental iodine anddisposed intermediate said source of iodine and said treatment station;an iodide/absorption collection resin in communication with effluentfrom said treatment station which receives said effluent from saidtreatment station prior to recirculation of the water stream; and aconversion station capable of conversion of iodide to iodine therebyproviding iodine for reuse in said process.
 19. An apparatus forconversion of iodide and/or iodine species to iodine (I₂) wherein saidiodine species for conversion by said conversion process are collectedfrom an iodine purification process, the apparatus comprising; a sourceof water for one or more water consuming applications and providing awater stream in said process; a delivery station intermediate saidsource of water and a treatment station; a source of iodine at thedelivery station and means to enable release into said water stream ofthe iodine; wherein, means to charge said water with a predeterminedconcentration of iodine; a monitoring electrode associated with saiddelivery station; wherein said predetermined concentration of iodineprovides a predetermined level of purification of said water stream andwherein said predetermined concentration of elemental iodine in saidwater stream is maintained by said electrode which facilitatescontrolled release of iodine from said source of iodine, means forrecovery from said water stream of said iodine and/or iodide and/orother iodine species derived from said iodine; and means for conversionof all said recovered iodine species derived from said iodine deliveredto said stream to iodine.
 20. An apparatus according to claim 19,wherein said conversion means comprises electrowinning means.
 21. Anapparatus according to claim 20, wherein said conversion means compriseschemical oxidants.
 22. An apparatus according to claim 21, wherein saidchemical oxidants are selected from permanganate, dichromate, hydrogenperoxide, bromate, iodate, chlorate, cerium, copper, chlorine andbromine.
 23. An apparatus according to claim 19, further including atleast one detection probe immersed in or adjacent the water stream andwhich is in communication with a computer wherein the predeterminedconcentration of iodine is maintained in the water stream.
 24. Anapparatus according to claim 19, further including sensors or detectionprobes immersed in the water stream wherein the predeterminedconcentration of iodine is maintained in the water stream.
 25. A methodof iodine purification of a water stream and/or objects therein; themethod including the steps of; a) providing a source of water for one ormore water consuming applications and providing a water stream as partof a the purification process; b) providing an iodine delivery stationintermediate said source of water and a treatment station; c) providinga source of iodine at the delivery station and means to enablecontrolled release into said water stream of said iodine; d) chargingwater with a predetermined concentration of iodine; e) maintaining thepredetermined concentration of iodine using an iodine specificelectrode; f) recovering said iodine and/or iodide and or other iodinespecies derived from said iodine from said fluid after saidpurification; g) converting the iodine and/or iodide and or other iodidespecies to iodine (I₂) for reuse in the purification process.
 26. Amethod according to claim 25, comprising the additional step ofcontrolling the release of said iodine into the water stream at apredetermined concentration which is proportionate to a level ofcontamination of said water stream.
 27. A method according to claim 25,comprising the further step of maintaining the predetermined iodineconcentration in the flow stream irrespective of the water flow rate,temperature of the water stream and level of contamination of saidwater.
 28. A method according to claims 25, comprising the further stepof providing the iodine in solid form as a fast dissolving high surfacearea iodine.
 29. A method according to claim 25, including theadditional step of performing the conversion as part of the process inline or remote from said process.
 30. A method according to claim 25,wherein the predetermined concentration of iodine in said water streamis maintained using electrodes or sensing probes immersed in said waterstream.
 31. A method according to claim 30, wherein a computer receivesdata on said iodine concentration from said electrodes or probes andactivates delivery of said iodine when the concentration falls below apredetermined minimum level.
 32. A method according to claim 25, whereinsaid conversion is performed by an electrowinning process.
 33. A methodaccording to claim 25, wherein said conversion is performed by achemical process using chemical oxidants.
 34. A method according toclaim 33, wherein said conversion is performed by the chemical processin which oxidants are selected from permanganate, dichromate, hydrogenperoxide, bromate, iodate, chlorate, cerium, copper, chlorine andbromine.
 35. A method according to claim 25, wherein said conversion isperformed using green sand as a catalyst.
 36. An apparatus for iodinedecontamination and purification of a water stream, the apparatuscomprising: a source of water for one or more water consumingapplications and providing a water stream in said process; a deliverystation intermediate said source of water and a treatment station; asource of iodine at the delivery station; means to enable release intosaid water stream of said iodine; an iodine specific monitoringelectrode associated with the delivery station which maintains theiodine in said water stream at a predetermined concentration to providea predetermined level of purification of said water stream and/orobjects in contact with said water stream in the treatment station. 37.An apparatus according to claim 36, further including a controller whichreceives a signal from the monitoring electrode relating to the actualconcentration of iodine in the water stream which compares iodineconcentration in the water stream with said predetermined concentration.38. An apparatus according to claim 37, wherein the controller is acomputer which enables controlled release of iodine from said deliverystation when said iodine falls below the predetermined concentration.39. An apparatus according to claim 38, wherein said computer preventsdelivery of said iodine from the delivery station when the iodineconcentration reaches the predetermined concentration.
 40. An apparatusaccording to claim 36, further comprising an iodide/absorptioncollection resin which receives effluent from said treatment station andwhich recovers iodide from said effluent.
 41. An apparatus formaintaining a concentration of elemental iodine within a predeterminedrange in a water stream used in a process for sanitizing water or in thedecontamination of consumables such as foodstuffs and in installationsusing water reticulation such as waste water, swimming pools, watersupplies, cooling towers, water tanks or town water by flushing orwashing with water having said predetermined concentration of iodine,said apparatus comprising: a water reticulation network including asource of main water supply for delivery to a treatment station; asource of iodine disposed intermediate said source of main water supplyand said treatment station; at least one receptacle for holdingelemental iodine and disposed intermediate said source of iodine andsaid treatment station; and an iodine specific monitoring electrodeassociated with the delivery station which maintains the iodine in saidwater stream at a predetermined concentration to provide a predeterminedlevel of purification of said water stream and/or objects in contactwith said water stream in the treatment station.
 42. A method of iodinepurification of a water stream and/or objects therein; the methodincluding the steps of; a) providing a source of water for one or morewater consuming applications and providing a water stream as part of athe purification process; b) providing an iodine delivery stationintermediate said source of water and a treatment station; c) providinga source of iodine at the delivery station and means to enablecontrolled release into said water stream of said iodine; d) chargingwater with a predetermined concentration of iodine; and e) maintainingthe predetermined concentration of iodine using an iodine specificelectrode.
 43. A method according to claim 42, further comprising thestep of recovering from said fluid said iodine and/or iodide and/orother iodine species derived from said iodine after said purification.44. A method according to claim 42, providing the additional step ofcontrolling the release of said iodine into the water stream at apredetermined concentration which is proportionate to a level ofcontamination of said water stream.
 45. A method according to claim 44,comprising the further step of maintaining the predetermined iodineconcentration in the flow stream irrespective of the water flow rate,temperature of the water stream and level of contamination of saidwater.
 46. A method according to claim 45, wherein the predeterminedconcentration of iodine in said water stream is maintained usingelectrodes or sensing probes immersed in said water stream.
 47. A methodaccording to claim 46, wherein a computer receives data on said iodineconcentration from said electrodes or probes and activates delivery ofsaid iodine when the concentration fall below a predetermined minimumlevel.
 48. A method according to claim 42, comprising the further stepof providing the iodine in solid form as a fast dissolving high surfacearea iodine.